Media captionNdileka Mandela: "A lot of comfort" in messages of support

Former South African leader Nelson Mandela is in a stable condition, his granddaughter says, though he remains critical.

Ndileka Mandela said the 94-year-old's family were taking comfort from messages of support from the public.

Meanwhile his daughter Makaziwe said he was "still there" and responding to touch.

South Africa's first black president has been in hospital in Pretoria since 8 June with a lung infection.

His health has worsened in recent days, prompting current President Jacob Zuma to cancel a foreign visit. He has now arrived back at the hospital.

At the scene

By Gabriel GatehouseBBC News, Pretoria

The gate outside the hospital is festooned with flowers, cards and placards. "Get well soon, Tata Madiba" many of them say, as they gather to pay tribute to a man who changed the face of a nation.

A group of children from a nearby township squealed with delight, as they released dozens of balloons into the air. Members of the ANC Youth League arrived singing songs, dressed in yellow T-shirts emblazoned with the words: "There is no born-free without a liberator."

Members of Nelson Mandela's family continue to visit his bedside, as they have done for the past 20 days. A granddaughter emerged from the hospital to thank well-wishers for their messages of support.

"They have given us strength to carry on," she said, "and to give him positive energy." But as she gathered a bunch of flowers from the pavement, she spoke of her anxiety at her grandfather's critical condition.

Emotional crowds have gathered outside, adding messages of support for Mr Mandela, known by his clan name Madiba.

Children released 94 balloons into the air in his honour.

Correspondents say South Africans now seem resigned to the prospect of his death.

"We don't like seeing Mandela going through so much pain, he has had a tough time in his life and he's gone through a lot of struggle. I think this struggle should get over sooner," Khulile Mlondleni told Reuters news agency.

"We are all going to feel bad when he passes [away], but at the same time we will be celebrating his life. He has done so many great things for this country," said 25-year-old John Ndlovu, quoted by the agency.

US President Barack Obama, who is in Senegal, described Mr Mandela as "a hero for the world".

"His legacy will linger on through the ages," he said.

Speculation warning

After visiting her grandfather in hospital, Mdileka Mandela said it was an anxious time for the family.

"He's stable and we'd like to say that we thank everybody for giving their support and praying with us... we are anxious as you know that he is critical but he's in a stable condition right now," she said.

"It's been hard, especially because of all of this - that we have to do everything in the public eye."

Nelson Mandela: Key dates

1918 Born in the Eastern Cape

1944 Joins African National Congress

1956 Charged with high treason, but charges dropped

1962 Arrested, convicted of sabotage, sentenced to five years in prison

Later Mr Mandela's daughter Makaziwe said that while the situation was serious he was still responsive.

"He doesn't look good, I'm not going to lie. But as I say, if we speak to him, he responds and tries to open his eyes. He's still there. He might be waning off, but he's still there," she told public broadcaster SABC.

She was also highly critical of the behaviour of the international media.

"There is a racist element with many of the international media where they cross boundaries - truly vultures waiting for when the lion has devoured the buffalo, it has gone overboard," Ms Mandela said.

Mr Zuma's spokesman Mac Maharaj said on Wednesday evening that Mr Mandela's condition had deteriorated over the weekend.

After consultations with doctors, Mr Zuma said he was cancelling his trip to a regional summit in the Mozambican capital Maputo.

The statement from his office said he "reiterated his gratitude on behalf of government, to all South Africans who continue to support the Madiba family".

The decision will only reinforce the impression that Mr Mandela's life is slipping away, the BBC's Mike Wooldridge reports from Johannesburg.

But later Mr Zuma's office warned against speculation about Mr Mandela's health, saying that announcements about his condition would come from the president himself or Mr Maharaj.

Media captionThe BBC's Karen Allen says there is a "mixture of emotions" outside the hospital